ES2899649T3 - Electric motor - Google Patents

Abstract

Fan system (10) with an electric motor (12), the electric motor (12) having a rotor (18) and the rotor (18) being rotatably mounted around a motor shaft (30), which has an end face (58), a fan wheel (14) being arranged on the rotor (18) without rotatability, characterized in that a contact element (56) is attached to the fan wheel (14), which is configured, in the assembled state, to rest on the front surface (58) of the motor shaft (30) and the rotor (18) establishing electrical contact, the contact element (56) presenting a first and a second section (60 , 62), the first section (60) being non-rotatably connected to the rotor (18) and the second section (62) resting rotatably on the front surface (58) of the motor shaft (30), and gripping the fan wheel (14) without the possibility of turning the first section (60) with the rotor (18).

Description

DESCRIPTION

Electric motor

The invention is based on an electric motor with a contact element according to the preamble of the independent claims.

State of the art

In the case of electromechanical switching of motors, electromagnetic waves are produced, which are radiated into the environment. These electromagnetic waves that are produced must be shielded.

DE 102012201 545 A1 discloses a device for shielding an electric motor from electromagnetic interference radiation, which is controlled by means of a synchronized signal. Provision is made for the rotor to be connected to the motor shaft via an electrically conductive connecting element, the connecting element being attached to the front surface of the rotor component. Documents WO2013/098309 and JPS61218344 describe additional fans with a connection element between the rotor and the motor shaft.

Disclosure of the invention

Advantages of the invention

The invention is based on a fan system with an electric motor, in particular an external armature motor and a fan wheel, the electric motor having a rotor and the rotor being rotatably mounted about a motor shaft, which it has a front surface, and the fan wheel is arranged without the possibility of rotation on the rotor. It is proposed that a contact element is attached to the fan wheel, which is configured, in the assembled state, to rest on the front surface of the motor shaft and the rotor by establishing electrical contact.

The fan system according to the invention with the method according to the invention with the features of the independent claims has the advantage that the contact element can be particularly easily assembled together with the fan wheel as a unit and at the same time, an additional fastening of the contact element to the rotor can be dispensed with. Other than that, the contact element can be easily centered through the fan wheel so that it is exactly aligned in the direction of an axis of rotation of the electric motor. Since the contacting of the motor shaft additionally takes place on the motor shaft at the end, unwanted squeaks can be minimized, which often occur and are perceived as annoying, in particular in the case of a radial contact of the motor shaft. These undesirable screeching noises in the case of a radial contact are often caused by natural vibrations in which components become trapped by the uneven rubbing and sliding of the radial contact on the motor shaft.

In the context of the present invention, the term motor shaft can be understood as a specific machine element which transmits a torque. Furthermore, hereinafter, by the term axis of rotation is meant an imaginary axis about which the rotor rotates, in the direction of an axis of rotation. In contrast to the motor shaft, which represents a specific machine element, the rotary axis is a purely imaginary axis.

Apart from that, in the context of the present invention, a front side of the motor shaft can be understood as that surface of the motor shaft which delimits the motor shaft laterally in the direction of the axis of rotation. In this sense, the term front surface is not limited to a flat surface; rather, the front surface can have any surface contour.

In an advantageous embodiment of the electric motor according to the invention, the electric motor is an external armature motor. Advantageously, in the case of such an embodiment, the shielding effect of the rotor itself is exploited.

The measures recited in the dependent claims result in advantageous refinements and improvements of the features recited in the independent claims.

The fan system according to the invention or an advantageous development is characterized in that the contact element has a first and a second section, the first section being non-rotatably connected to the rotor and the second section resting rotatably on the front surface of the motor shaft.

Preferably, the second section presses in the axial direction with a prestressing force on the front surface of the motor shaft. Through the use of a contact element with a second section, which, in the installed state, presents a pre-tension in the axial direction, the second section exerts a compressive force on the front surface and thus applies a recoil force to the front surface in the direction of a spring. In this way, a permanent contact between the elastic element and the end face of the motor shaft can be ensured.

In this context, the axial direction is essentially to be understood as the extension direction of the axis of rotation. In this sense, however, it is not necessary that the entire clamping force, with which the second section presses on the front surface, runs in the direction of the axis of rotation. It is also conceivable that the clamping force is arranged at a certain angle to the end surface and the force vector of the clamping force has a percentage in the direction of the axis of rotation and a percentage perpendicular to the axis of rotation. In this sense, it is only essential for the invention that the force vector of the clamping force is larger in terms of quantity in the axial direction.

In a particularly simple and inexpensive embodiment of the invention, the contact element is configured in the form of a strip and extends in the radial direction. In this way, the contact element attached to the fan wheel can be clamped between the rotor and the fan wheel in a particularly simple and secure manner and, in the installed state, can make contact with the motor shaft on the left side. frontal.

In this context, by strip shape it should be understood in particular that an expansion of the contact element in the main direction of extension amounts to a multiple, preferably at least twenty times, of an expansion of the contact element in any perpendicular direction. relative to the main extension direction. Particularly preferably, the contact element has an essentially triangular, rectangular or trapezoidal cross-section in a section plane perpendicular to the main direction of extension. A convex rectangular or trapezoidal cross-sectional shape is also conceivable.

Also, in this context, by extension in the radial direction it should be understood that the main direction of extension of the contact element is in the radial direction. However, it is also conceivable and suitable for fulfilling the function that certain sections of the contact element extend proportionally in the axial direction. In this sense, it is only essential for the invention that the contact element has a main extension in the radial direction.

In the invention, the fan wheel locks the first section of the contact element with the rotor without the possibility of rotation. For this purpose, the fan wheel is non-rotatably connected to the rotor, whereby the contact element arranged between the rotor and the fan wheel is braced. In this connection, the fan wheel acts in the direction of a holding means on the contact element and presses the contact element against the rotor. The force drag provided in this way prevents twisting of the contact element during operation. It should be mentioned at this point, however, that a non-rotatable connection can only be understood as an essentially non-rotatable connection. Thus, for example, it is conceivable that, when the rotor is started, the contact element has an inclined plane phase and is only connected to the rotor without the possibility of rotation when during rolling operation.

A particularly simple and robust construction of the contact element within the given housing construction space can be implemented in that the second section of the contact element according to the invention is essentially V-shaped or U-shaped, with a first section adjoining the second section in each case radially.

By the term "V-shaped" used in the present application can be understood a conformation of the second section that is similar to the letter "v" of the German alphabet. In this sense, the legs of the second V-shaped section of the contact element do not have to run in a straight line, nor do they have to converge to form a point. It is only essential for the invention that the area, central to the axis of rotation, of the second V-shaped section is arranged at a distance in the axial direction from the distal areas, in each case relative to the axis of rotation. turn, of the second V-shaped section. The first sections in each case adjoin radially the in each case distal areas of the V-shaped section.

Likewise, by the term "U-shaped" one can understand an embodiment of the second section, the shape of which is similar to the letter "u" of the German alphabet. In this case, it is also not crucial that the legs of the second U-shaped section run parallel and meet in a bend. It is also essential for the invention, in the case of such an embodiment, that the central area, with respect to the axis of rotation, of the second U-shaped section is arranged at a distance in the axial direction from the areas in each case distal to the second section are U-shaped and the first sections adjoin the second section in each case radially. In this way, the axial spatial distance between the front surface of the motor shaft can be optimally bridged and the contact element is able to apply a sufficiently large clamping force for a in permanent contact with the front surface of the motor shaft.

Preferably, the second section also has an essentially flat contact area extending in the radial direction, the sliding contact area resting on the motor shaft.

Particularly simple production and handling can result from the fact that the contact element according to the invention is configured in one piece, in particular as a stamped part or stamped and bent part. The one-piece embodiment of the contact element has advantages in terms of production, as well as assembly effort and assembly speed. The use of stamping or stamping and bending technology enables economical production of the contact element from a tape material in a stable and economical manufacturing process.

Compared to contact elements made in one piece from components of the electric motor or fan wheel, such a contact element as an additional component according to the invention has the advantage that it can be manufactured individually. from a different material that is optimally designed for its function to compensate for differences in potential, the material requirements being able to be optimally matched to the loading regimes during operation.

In an advantageous embodiment of the fan system according to the invention, the rotor has a cylindrical bearing seat, which extends in the axial direction, arranged centrally with respect to the motor shaft, the contact element engaging according to the invention in the bearing seat. Such a bearing seat is designed to accommodate the rotor bearing such that the rotor and fan wheel are rotatably mounted and their position is locked both radially and axially. Preferably, the cylindrical or ring-shaped bearing seat is formed as a recess or groove in the rotor housing, so that the bearing seat can be formed by simple deep-drawing or in an injection molding process. .

In this context, by the term "engage" it can be understood that the contact element, in the assembled state, protrudes in the axial direction into the space formed by the bearing seat.

Preferably, the first sections each have a free end, the free end being attached to the fan wheel. In this context, the term "fix" can be understood as meaning that the contact element is attached to the fan wheel in a captive manner, so that the contact element remains on the fan wheel during mounting and can be mounted. no possibility of rotation in the rotor as a common unit. Such a captive insertion enables quick and easy handling and assembly of the fan system according to the invention.

In an advantageous embodiment, an engagement element corresponding to the bearing seat can be arranged on the fan wheel, which engages in the bearing seat in the installed state. This has the advantage that the fan wheel can be centered particularly easily, so that the fan wheel can be aligned exactly in the direction of the axis of rotation and thus has less susceptibility to noise and less imbalance.

Preferably, the free ends of the first sections are pressed into the engaging element, the term pressed being able to be understood in this context as an insertion in a captive manner, so that the contact element does not fall off the fan wheel or well of the gear element during assembly when exposed to the force of gravity. It is also conceivable that the engagement element has at least one rib, the free ends of the first sections bending in the depression formed by the at least one rib in the direction of a flexible flange.

In a further particularly advantageous embodiment of the fan system according to the invention, a sliding contact extending in the axial direction is formed on the second section of the contact element. Through the configuration of a sliding contact, the contact surface between the front surface of the motor shaft and the contact element can be minimized. This can have a positive impact, in particular, on minimizing noise and friction losses. Through the extension of the sliding contact in the axial direction, the required pretension for the corresponding clamping force in the axial direction can be guaranteed.

The sliding contact is preferably convexly shaped. Such a curved embodiment of the support area can be produced in a particularly simple and inexpensive manner by plastic tensile and compression forming of the strip-shaped contact element. In the context of the present invention, the term bulging can be understood as any surface contour that exhibits bulging or curvature. Such a convex contour can be formed, for example, by a protrusion that has a convex or hemispherical shape.

The effect of minimized friction can be exploited particularly preferably in a further embodiment in that the end face of the motor shaft of the fan system according to the invention is designed to taper in the direction of movement. axis of rotation. The contact surface of the contact element on the shaft is reduced by the pointed end face, which means that friction can be minimized.

Such an embodiment of the fan system according to the invention with a pointed end surface of the motor shaft and/or a sliding contact arranged in the second section of the contact element can enable simple and precise centering of the contact element, whereby the relative speeds between the contact element and the motor shaft in the area of the sliding contact are minimized.

Preferably, the contact element is configured to deflect electromagnetic interference radiation. In this way, the emission of unfavorable interfering radiation can be reduced.

He drew

Embodiments of the invention are shown schematically in the figures and are explained in more detail in the following description. They show:

Fig. 1 a schematic representation of a fan system according to the invention,

FIG. 2 a fragment of the fan system according to the invention according to FIG. 1, FIG. 3 a first embodiment of the contact element according to the invention in a perspective view,

FIG. 4 a second embodiment of the contact element according to the invention in a perspective view,

FIG. 5 a perspective view of an embodiment of a fan wheel according to the invention,

Fig. 2 a schematic representation of an embodiment of a fan system according to the invention.

Description

Figure 1 shows a fan system 10 with an electric motor 12 and a fan wheel 14. The fan wheel 14 has a plurality of fan blades, which are designed to convey cooling air during rotation of the fan wheel. fan 14. The electric motor 12, shown in FIG. 1, exemplified as an external armature, of the fan system 10 has a stationary part, the stator 16, and a rotating part, the rotor 18. An electric motor of the type of an external armature motor, as shown by way of example in Figure 1, is characterized in that the radially inner part is stationary during operation, while the radially outer part rotates. A plurality of windings 20 are arranged on the stator 16. The rotor 18 in turn has magnets 22. If current flows through the windings 20, then the magnetic field of the stator 16 drives the rotor 18.

It should be noted that the fan system 10, in particular the electric motor 12 in Figure 1, is only schematically represented, since the structure and functionality of a suitable electric motor 12 are sufficiently known from the state of the art, so that in this case, for the purpose of conciseness and simplicity of description, a detailed description of the fan system 10 is omitted. In addition, it should be noted that the electric motor 12 of the fan system 10 is represented as an external armature motor by way of example only and not to restrict the invention, since the invention can also be used in the case of an internal armature motor.

The windings 18 of the electric motors 12 are generally supplied with pulse width modulated signals during operation, which can cause interference fields. In this sense, the electromagnetic interference radiation generally occurs in the windings 20 or the magnets 22. From the windings 20 or the magnets 22, the interference radiation can result in a disturbance of other electronic systems and components, which are arranged in the environment of the fan system 10. In addition to influencing the components of the environment by the electric motor 12, disturbing radiation from the environment can also impair the functionality of the fan system 10 in reverse. Therefore, the electric motor 12 according to the invention should shield the windings 20 and the magnets 22 as much as possible in all directions.

In the case of an electric motor 12 of the external armature type, as shown in FIG. 1, such shielding can be achieved, among other things, by means of a rotor 18 arranged as close as possible to the stator. 16. As can be clearly seen in FIG. 1, the rotor 18 is essentially cup-shaped. In this sense, this cup-shaped embodiment of the rotor 18 forms a shield for the windings 20 and the magnets 22, which are arranged inside the cup-shaped rotor 18. For this purpose, the cup-shaped rotor 18 has a first section 24 which extends in the radial direction. This first section 24 of the rotor 18 forms the bottom of the cup-shaped rotor 18. In addition to the first section 24, which extends in the radial direction, of the rotor 18, the rotor 18 has a second section 26, which is arranged on the outer edge of the rotor 18 and forms a circumferential cylindrical side wall of the rotor 18.

The open area of the rotor 18 opposite the bottom 24 of the cup-shaped rotor 18, as can be clearly seen in FIG. 1, is shielded by a motor mount 28. The arrangement of the cup-shaped rotor 18 as well as the Motor support 28 functioning as a cover results in an essentially closed space for magnets 20 and windings 22, which is shielded in all directions by electrically conductive surfaces.

In the case of the embodiment shown in FIG. 1, the motor shaft 30 is non-rotatably connected to the motor mount 28 or to the stator 16. Such a non-rotatable connection can be provided in particular by inserting the motor shaft 30 into the motor support 28. As shown in FIG. 1, the motor shaft 30 has a firmly fixed end 32, a free end 34 and a pivot axis 36, around which rotor 18 with fan wheel 14 and stator 16 are rotatably mounted relative to one another.

As shown in FIG. 1, the axis of rotation 36 runs in the direction of an imaginary straight line extending to infinity, in particular centrally through the motor shaft 30 and corresponds to the central axis of the motor shaft 30. For the rotatable mounting of the rotor 18 with respect to the stator 16 about the axis of rotation 36, a cylindrical bearing seat 40 is arranged on the rotor 18, on its side facing the motor shaft 30, which extends in the axial direction. A bearing 42 is arranged inside the bearing seat 40 of the rotor 18. As shown in FIG. 1, the bearing 42 has two bearings 44, 46, both bearings 44, 46 with their respective outer ring 50 sitting in the bearing seat 40 of the rotor and with its corresponding inner ring 48 without the possibility of rotation on the motor shaft 30.

If the electric motor 12 is started, then the rotor 18 is set in rotation. To drive the fan wheel 14, it is fixed non-rotatably on the rotor 18. As schematically indicated in FIG. 1, for Therefore the first section 24 of the rotor 18 can be connected to the fan wheel 14 via a screw connection 54. However, other fixing means are also conceivable.

To prevent the rotor 18 from taking over the function of a high-frequency antenna and possibly worsening the disturbance problem, the rotor 14 must be brought into contact with a ground potential 52.

In order to bring the rotor 18 into contact with ground potential 52, the rotor 18 must be connected to the motor shaft 30 in an electrically conductive manner, which in turn has been pressed into the motor mount 28 and is made of itself of an electrically conductive material and therefore rests on ground potential 52. Such a coupling between rotor 18 and motor shaft 30 cannot as a rule be provided via the bearings 44 themselves. , 46, including their respective bearing shells, since these have an oil-filled bearing space, which has the consequence that no sufficiently stable ohmic connection can be provided.

However, in order to provide a sufficiently stable ohmic connection between the rotor 18 and the motor shaft 30, a contact element 56 made of an electrically conductive material is attached to the fan wheel 12. In the assembled state, as shown in FIG. 1, the contact element 56 rests in electrical contact on the rotor 18 and the front surface 58 of the motor shaft 30.

In order to bring the two components (the rotor 18 and the motor shaft 30) into contact, the contact element 56, as shown in FIG. 1, has two sections 60, 62. In this sense, the first section 60 of the contact element is non-rotatably connected to the first section 24 of the rotor 18; the second section 62 rests slidably on the front surface 58 of the motor shaft 30.

As can be clearly seen in FIG. 1, the rotor 18 and fan wheel 14 components clamp the first section 60 of the band-like contact element 56 in the assembled state in the sense of a clamping connection between them. . The clamping connection between the fan wheel 14 and the contact element 56 is applied by means of a screw connection 54. The screw forces generate a normal force and a tangential or frictional force on the contact element 56, so that the contact element 56 rests without the possibility of rotation on the rotor 18 and a stable ohmic connection is created between the contact element 56 and the rotor 18.

As shown in FIG. 1, the contact element 56 according to the invention each has a free end 64 in its first sections 60. These free ends 64 are attached to the fan wheel 14 in a captive manner. In the case of the embodiment shown in Figure 1, the free ends 64 of the first sections 60 are clipped for this purpose into the corresponding housing slots 66 of the fan wheel 14. However, it should be expressly mentioned at this point that a fan system 10 according to the invention is not limited to such an embodiment with a clip-on contact element 56 . Thus, any embodiment in which the contact element 56 is captively attached to the fan wheel in a first mounting step is conceivable and sufficient for the function to be fulfilled.

During assembly, the contact element 56 according to the invention is installed with its second section 62 under a defined pre-tension, so that the second section 62 of the contact element 56 is pressed in the axial direction on the front surface 58 of the motor shaft 30 with a clamping force sufficient to fulfill the function. In other words, the contact element 56 acts in the direction of a spring, which applies a return force on the front surface 58.

FIG. 1 shows a contact element 56 configured in one piece, which is configured in particular as a stamped and bent part. It should be mentioned at this point, however, that the contact element 56 is not limited to such an embodiment shown in FIG. 1. Thus, for example, embodiments are also conceivable in which the first and the second section 60, 62 are produced in two parts and connected to each other in a further manufacturing step.

FIG. 2 shows the contact element 56 according to the invention analogously to FIG. 1 in an enlarged representation. As described above, the contact element 56 is configured as a ribbon-shaped element, which extends essentially in the radial direction, ie in a direction perpendicular to the imaginary axis of rotation 36 . As can be seen further in FIG. 2, the strip-shaped contact element 56 rests with its two first sections 60 in each case on the front surface 65 of the first section 24 and bridges the inner space 68, which is encloses by the cylindrical bearing seat 40.

As shown in Fig. 2, the front surface 58 of the motor shaft 30 and the front surface 65 of the first section 24 of the rotor 18 are spaced apart from each other in the axial direction by an axial distance 70. In In this sense, the motor shaft 30 ends with its free end 34 in the interior space 68 of the cylindrical bearing seat 40. In order to bridge the axial distance 70, the second section 62 is essentially V-shaped. In this way, the contact element 56 according to the invention can bridge the axial distance 70 and rest both on the front surface 65 of the rotor 18 as on the front surface 58 of the motor shaft 30.

At this point, however, it should be mentioned in detail that other embodiments of the second section 62 of the contact element 56 are also conceivable, which are configured to bridge the axial distance 70. Thus, for example, it is also possible It is conceivable that the second section 62 is U-shaped and rests slidably with its axially lowest point on the end surface 58 of the motor shaft 30. In this sense, it is only essential for the invention that the contact element 56 is contact both rotor 18 and motor shaft 30.

Apart from that, a fan system 10 according to the invention is not limited to such a contact element 56, which rests on the front surface 65 of the first section 24 of the rotor 18. Thus, for example , it is also conceivable that the contact element 56 according to the invention comes into radial contact with the rotor 18, for example in the cylindrical bearing seat 40, or the contact element 56 in the form of a ribbon for optimal positioning. and for compensation of potential differences in the curvature 72 rests between the first section 24 of the rotor 18 and the bearing seat 40.

In particular, in the case of an embodiment, as depicted in FIG. 5, with an engagement element 84, corresponding to the bearing seat 40, which is arranged on the fan wheel 14, a gear element contact 56, which rests on the curvature 72 of the rotor 18 in the installed state, can be seized by the fan wheel 14 with the corresponding meshing element 84.

As already explained, a first section 60 adjoins the second section 62 in each case radially. In the assembled state, this first section 60 rests on the rotor 18 without the possibility of rotation in a support area 82 (shown in FIG. 3). Apart from that, the first sections 60 each have free ends 64. These free ends 64 are attached to the fan wheel 14. In this regard, it is essential for the invention that the contact element 56 is attached in a captive manner to the fan wheel 14 in a first manufacturing stage and then placed on the rotor 18 together with the fan wheel 14 as a unit in a second manufacturing stage in such a way that the contact element 56 rests without possibility of rotation in rotor 18 and rotatably on motor shaft 30.

In the case of the embodiment shown in FIG. 2, the free ends 64 of the first sections 60 of the contact element 56 are bent for the purpose of captive fixing on the fan wheel 14, so that extend in the axial direction. In this sense, the free ends 64 engage in receiving grooves 66 in the fan wheel 14. For captive fastening, the free ends 64 each have a shoulder 74, which protrudes radially in a corresponding step 76 of the grooves. housing 66, so that the contact element 56 is clipped with its free ends 64 in the recess 65 during assembly. The undercut in the radial direction between the step 76 and the molded shoulder 74 in the radial direction of the free ends 64 forms a correspondingly shaped engagement during mounting, so that the contact element 56 cannot fall out of the gear wheel. fan 14 in the axial direction.

In the case of the embodiment shown in FIG. 2, the projections 74 of the free ends 64 are configured as convex elements or channel-shaped elements. According to the invention, however, such shoulders 74 are not limited to such a domed embodiment. Also conceivable are embodiments that are suitable for engaging correspondingly with the step 76 or the receiving grooves 66 and engaging the corresponding step 76 in the radial direction.

As can be clearly seen in FIG. 2, the second V-shaped section 62 has an essentially flat contact area 78 extending in the radial direction, the contact area 78 slidingly resting on the motor shaft 30.

To minimize friction between the second section 62 of the contact element 56 and the front surface 58 of the motor shaft 30 and to provide a deflection and, accompanied by it, a sufficiently large recoil force of the second section 62 of the contact element 56, in the center of contact area 78 an additional shoulder is molded as sliding contact 80. Therefore, in the assembled state, only sliding contact 80 comes into contact with front surface 58 of motor shaft 30.

In the case of the embodiment shown in FIG. 2, the sliding contact 80 is designed as a curved element in the axial direction, in particular as a hemispherical element, so that the contact surface of the contact element 56 on the front surface 58 is minimized by only punctiform support. According to the invention, however, such a sliding contact 80 is not limited to a hemispherical embodiment as shown in Fig. 2. Other pointed shapes are also conceivable, which are suitable for putting on contact on the front side axially the front surface 58 in a contact area as small as possible.

The following figures 3 and 4 show in each case a perspective representation of a contact element 56 according to the invention.

FIG. 3 shows the strip-shaped contact element 56 analogously to FIGS. 1 and 2. First sections 60 each adjoin on both sides the essentially V-shaped second section 62 arranged centrally. These first sections 60 are configured to rest on the front surface 65 of the rotor 18 in the assembled state. The main direction of extension of the contact element 56, as shown in Fig. 3, extends in the radial direction. For the captive fastening of the contact element 56 on the fan wheel 14, the free ends 64 are in each case deflected by 90° from the main radial direction of extension. In this regard, in the assembled state, the free ends 64 engage in the corresponding receiving grooves 66 in the fan wheel 14.

On the free ends 64, as can be clearly seen in FIG. 3, projections 74 are arranged, which in turn extend in the radial direction. In the clipped state, these shoulders 74 form a form lock with a step 76 molded into the receiving grooves 66 (shown in FIG. 2).

As can also be clearly seen in FIG. 3, the contact element 56 according to the invention has a flat contact area 78 in the center that extends in the radial direction. In the center of the contact area 78, a shoulder extending in the axial direction is molded as a sliding contact 80. In the case of the embodiment shown in Fig. 3, the sliding contact 80 has a hemispherical outline.

As already explained, in the assembled state, the contact element 56 rests both slidably on the motor shaft 30 and non-rotatably on the rotor 18. For this purpose, the first sections 60 each have a support element 82, which is molded on the respective first section 60 and is preferably convex or channel-shaped. Therefore, in the assembled state, as already described above, the fan wheel 14 seizes the first sections 60 of the contact element 56 with the rotor 18, or the front surface 65 of the rotor 18. In this regard , the corresponding support element 82 is pressed onto the rotor 18, whereby a stable ohmic connection can be provided between the rotor 18 and the contact element 56.

Figure 4 shows a further embodiment of a contact element 56 according to the invention, the which is fixed in a first manufacturing step on the fan wheel 14 and in a second manufacturing step is connected to the electric motor 12 together with the fan wheel 14 without the possibility of rotation in such a way that the contact element 56 rests with its first sections 60 without the possibility of rotation on the rotor 18 and comes into contact with its second section 62 with sliding on the motor shaft 30.

As can be seen in FIG. 4, the contact element 56 has two substantially strip-shaped units analogous to FIG. 3, which are placed one above the other in the shape of a cross. Starting from the centrally arranged second section 62, which in the assembled state rests slidably on the motor shaft 30, four first sections 60 extend in the radial direction. Analogous to FIG. 3, the contact element 56 of FIG. 4 also has a flat, centrally arranged contact area 78 extending in the radial direction. Also molded in the center of the contact area 78 is a sliding contact 80 extending in the axial direction, which is shown covered in Figure 4 due to the selected perspective.

Analogous to the embodiment of the contact element 56 in FIG. 3, the first four sections 62 each have a bent free end 64 with a channel-shaped shoulder 74 for fastening to the rotor. As already explained, in the assembled state, the contact element 56 rests both slidably on the motor shaft 30 and non-rotatably on the rotor 18. To this end, the first four sections 60 each have a support element 82, which are molded onto the first sections 60 in each case and are preferably convex or channel-shaped. Therefore, in the assembled state, as already explained, the fan wheel 14 seizes the first four sections 60 of the contact element 56 with the rotor 18, or the front surface 65 of the rotor 18. In this regard , the four bearing elements 82 are pressed onto the rotor 18, whereby a stable ohmic connection can be provided between the rotor 18 and the contact element 56. Through the use of four bearing areas 82, the contact surface can be increased to improve the ohmic connection.

It should be noted at this point that the number of the first sections 62 can be varied as desired. In this way, for example, by further increasing the number of first sections 62, the support surface can be enlarged.

FIG. 5 shows a fragment of a perspective view of a further embodiment of the fan wheel 14. FIG. 5 shows the side facing the electric motor 12 in the installed state and shows the fragment of the fan wheel. fan 14 arranged centrally in the area of motor shaft 30.

As can be seen in FIG. 5, an annular gear element 84 is arranged on the fan wheel 14, which in the assembled state extends in the axial direction, i.e. in the direction of the motor shaft. 30. This collar-shaped, circumferential engagement element 84 engages in the bearing seat 40 of the rotor 18 in the assembled state. Preferably, in this regard, the outer surface 86 of the engagement element 84 rests on the wall extending in the axial direction of the bearing seat 40 in the direction of a shaft-hub connection and thus forms a connection in positive and positive engagement between the rotor 18 and the fan wheel 14. Such an engagement element 84 enables exact centering of the fan wheel 14.

As shown in FIG. 5, the gear element 84 has several ribs 88, which are aligned parallel to the axis of rotation 36 of the fan wheel 14 or rotor 18. The ribs 88 are evenly distributed on the surface. circumferential direction around the axis of rotation 36 on the fan wheel 14. An unequal arrangement is also conceivable. The ribs 88 are connected in an upper section by means of an annular section 90. Therefore, the annular section 90 provides for an axial stabilization of the ribs 88. Alternatively, the annular section 90 can also be configured as a partially annular 90 and can connect only a part of the ribs 88 in each case to each other. In the embodiment, the ribs 88 are partially annularly configured and aligned in the circumferential direction. Apart from that, they extend in the axial direction parallel to the axis of rotation 36. However, other cross sections, such as triangular, rectangular or circular, are also conceivable. The ribs extending in the axial direction abut each other in the circumferential direction with a depression 92 between them. In a further embodiment of the fan system 10 according to the invention, the free ends 64 of the ribbon-shaped contact element 56 can be pressed into these depressions 92 and thus connected to the fan wheel. fan 14 in a captive way.

Preferably, the radial depth of the depressions 92 is dimensioned such that the embedded ribbon-shaped contact element terminates flush or flush with the outer surface 86 of the engaging element 84, so that the contact element 56 is press into bearing seat 40 in the assembled state. By means of the surface pressure thus applied between the free ends 64 of the contact element 56 and the bearing seat 40 of the rotor 18, a stable ohmic connection can be provided for compensation of the potential differences between the rotor 18 and stator 16.

It should be mentioned at this point that the number and shape of the ribs 88 shown here can be vary as desired. Furthermore, it is also conceivable that the free ends 64 of the contact element 56 according to the invention protrude in the axial direction beyond the depression 92, so that the contact element 56 according to the invention is pressed against the curvature. 72 of the rotor 18 in the assembled state.

Figure 6 shows a further embodiment of the fan system 10 according to the invention. Fig. 6 corresponds to the embodiment according to Fig. 1 with the difference that the end face 58 of the motor shaft 30 is configured so that it ends in a point in the extension direction of the axis of rotation 36. In other In other words, the motor shaft 30 has, at its free end 34, a conical or frustoconical shape. By designing a pointed front surface 58 symmetrically with respect to the axis of rotation 36, a centering with precise tolerances of the contact element 56 can be guaranteed, whereby the relative velocities between the contact element 56 and and the motor shaft 30 in the support area.

In addition to a rotationally symmetrical pointed front surface 58, as shown in Fig. 6, in which the front surface 58 has been chamfered to form an essential part, also conceivable and sufficient for the fulfillment of the function additional pointed shapes, such as, for example, a domed or semicircular front surface 58 .

It should be noted that, with regard to the exemplary embodiments shown in the figures and in the description, a wide range of possible combinations of the individual features with each other is possible. In this way, for example, the design of the end face and/or the adjacent shoulder can be adapted to the permissible relative speeds, friction coefficients and squeaks. The design of the contact element as a one-piece or two-piece component can also be tailored to product requirements, such as, for example, component costs or retrofitting of an existing system.

Claims (14)

1. Fan system (10) with an electric motor (12), the electric motor (12) having a rotor (18) and the rotor (18) being rotatably mounted about a motor shaft (30), the which has a front surface (58), a fan wheel (14) being arranged non-rotatably on the rotor (18), characterized in that a contact element (56) is attached to the fan wheel (14), which is configured, in the assembled state, to rest on the front surface (58) of the motor shaft (30) and the rotor (18) establishing electrical contact, the contact element (56) presenting a first and a second section (60, 62), the first section (60) being non-rotatably connected to the rotor (18) and the second section (62) rotatably resting on the front surface (58) of the motor shaft (30), and seizing the fan wheel (14) without the possibility of turning the first section (60) with the rotor (18). Fan system (10) according to one of the preceding claims, characterized in that the second section (62) presses in the axial direction with a pre-tensioning force on the end face (58) of the motor shaft (30) . Fan system (10) according to one of the preceding claims, characterized in that the contact element (56) is configured in the form of a strip and extends in the radial direction. Fan system (10) according to one of the preceding claims, characterized in that the second section (62) is essentially V-shaped or U-shaped and a first section (60) adjoins the second section (62) in each case radially. Fan system (10) according to one of the preceding claims, characterized in that the second section (62) has an essentially flat contact area (78) extending in the radial direction, the contact area (78) resting on with sliding on the motor shaft (30). Fan system (10) according to one of the preceding claims, characterized in that the contact element (56) is designed in one piece, in particular as a stamped and bent part. Fan system (10) according to one of the preceding claims, characterized in that the rotor (18) has an axially extending cylindrical bearing seat (40) arranged centrally with respect to the motor shaft ( 30), engaging the contact element (56) in the bearing seat (40). Fan system (10) according to one of the preceding claims, characterized in that the first sections (60) each have a free end (64), the free end (64) being attached to the fan wheel (14). ). Fan system (10) according to one of claims 7 or 9, characterized in that an engagement element (84) corresponding to the bearing seat (40) is arranged on the fan wheel (14), the element engaging gear (84), in the assembled state, in the bearing seat (40). Fan system (10) according to claim 9, characterized in that the free ends (64) of the first sections (60) are pressed into the engagement element (84). Fan system (10) according to one of the preceding claims, characterized in that a sliding contact (80) extending in the axial direction is formed on the second section (62) of the contact element (56). 12. 13. Fan system (10) according to claim 12, characterized in that the sliding contact (80) is convex. Fan system (10) according to one of the preceding claims, characterized in that the end surface (58) of the motor shaft (30) is designed to be pointed in the axial direction. 14. Process for the production of a fan system (10) according to claims 1 to 13, with the following process steps: - fixing a contact element (56) on a fan wheel (14) - non-rotatable coupling of the fan wheel (14) to a rotor (18), the contact element (56) seizing essentially non-rotatably with the rotor (18) and the contact element (56) resting on rotatably on a front surface (58) of a motor shaft (30).